I'm an avid junior road racer, I put on around 250 miles a week. I work at a bike shop and have seen every 2010 group. I have to work on my ultegra stuff probably three times a week and I take very very good care of my bikes. For the price paid I can only say it is not worth it. My sram force bike is lighter, stiffer, and longer lasting. I have had to tune up the bike twice the whole season. My shimano stuff constantly misses shifts and needs work much too often. All i can say is get force, it works better. Your paying less money for a better, and lighter (for the weight weeny) group. Dont waste your money. Sram shifters can be rebuilt, if your shimano shifters break you need to get another set. My teammates who use even sram rival have less problems then me. GO SRAM

Strengths: The Strongest argument against buying Dura Ace.
So quiet. So smooth

Weaknesses: Not as Shiney as Dura Ace. Hard to build a fifteen pound bike with it.

Bottom Line:

Best deal going on components. I've raced road and cross on Ultegra 6600 and would not race anything else (unless it's on someone else's bill). I tried SRAM Rival for the Weights savings, but switched back after less than a year.

Weaknesses: Probably the weight, which people will inevitably compare to its big brother(or sister, are groupos female? Like boats and ships?)Dura Ace.

Bottom Line:

Buy and forget best describes this groupo. I had my Ultegra since September 2005. 3 years and lots of crashes later, it's still smooth and working! The shifters are the highlight of the group to me. They can be mounted really high on the bars, which provides me with a stable platform when I standing on my pedals. The throw is pretty short and shifting on a dime is easy. Overall I highly recommend this group for anyone who wants a workhorse group with a reasonable price.